View Full Version : Trane TUA single stage problems??
11-20-2006, 07:50 PM
Went to work on a Trane 5-6 yr old TUA single stage with silicon nitride. Found a ignitor totally blown apart. I put in a new one and now I get a number 3 fault, which says a bad pressure switch. I confirmed that its ok and still get a #3. I returned with a new board and no more #3, but now I get a #9...Bad Ignitor. I get 15 ohms across the HSI. All voltages are correct zero volts across common. Upon start up I do get a very short amount of ignitor warm up but then after 1/2 to 1.5 seconds, the inducer shuts down and main blower turns on. This is on a new board. The inducer is running strong and the PS is not dropping out. I am thinking DOA board. Any input?
11-20-2006, 08:03 PM
Make sure the unit has a good ground and that the polarity of both the line voltage and control voltage is correct. Make sure good contact is being made inside the plugs.
If you are checking the voltage to the ignitor with the ignitor unplugged, or if there is a bad connection in the wiring to the ignitor, it will give you the ignitor error code.
The White Rogers boards will also do that if the line voltage and control voltage to the board are not in phase with eachother, or are not the same polarity.
11-20-2006, 08:28 PM
Yes you are correct and I did check the low and line polarity against the schematic. The ground that is providid in the factory handy box in the furnace was not connected and never has been. This house is not old. Everything in conduit all the way to the furnace. I connected the factory cabinet ground to one of the water pipes to check and see and nothing. This is a strange one. I have been an American Standard dealer for 13 yrs. now and never came across this type of problem or at least something that left me scratching my head like this one.
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